Dependencies is not possible to set dynamically

[dominx99]

Hi, It would be nice to have possibility to set dependencies of a system dynamically based on the device type, like in given example:

const isMobile = scene.sys.game.device.os.android || scene.sys.game.device.os.iOS || scene.sys.game.device.os.iPad || scene.sys.game.device.os.iPhone;
const moveClientPrediction = new MoveClientPredictionSystem();
moveClientPrediction.dependencies = [isMobile ? 'KeyboardMoveController' : 'JoystickMoveController'];

addSystem(moveClientPrediction)

Currently dependencies is readonly